前几天搞定了贪吃蛇自动寻路算法……

写了几天，搞定了贪吃蛇自动寻路……目前在20*20的格子上面可以稳定跑到100+分，200+的话……看运气吧o(╯□╰)o，总之算法还有很多可以修改的地方，而且UI部分还有部分没写的……
总结下：这次写的话主要算法用的是BFS，没有用A*算法，因为太复杂了，用JS实现感觉好难，所以暂时没有写……然后有两种策略，一种是吃到食物还能找到自己尾巴的话就直接去吃食物，如果发现找不到吃食物的路径OR吃了就会死那么就在头部附近找一个格子，格子满足两个条件：一个是到了这个格子之后可以找到去尾巴的路，第二个是这个格子离食物最远……其实策略主要是看了别人写的贪吃蛇算法搞出来的，可惜的是目前还是不能铺满整个格子orz……算法还得改啊哈哈哈o(╯□╰)o
代码如下【只放JS了】：

(function () {
    /*全局变量*/
    var g = {
        //获得or设置盒子的attribute
        attr : function (x, y, att, name) {
            var d = document.getElementById("box_" + x + "_" + y);
            if (d && name)
                d.setAttribute(att, name);
            else if (d)
                return d.getAttribute(att);
        },
        //随机创建点
        create : function (start, end) {
            return Math.floor(Math.random() * (end - start) + start);
        },
        addHandler: function (ele, type, handler) {
            if (ele.length === undefined) { if (ele.addEventListener) { ele.addEventListener(type, handler, false); } else if (ele.attachEvent) { ele.attachEvent("on" + type, handler); } else { ele['on' + type] = handler; } }
            else if (ele.length === 0) { console.log("The element is null!"); return false; }
            else { for (var i = 0; i < ele.length; i ++) { if (ele[i].addEventListener) { ele[i].addEventListener(type, handler, false); } else if (ele[i].attachEvent) { ele[i].attachEvent("on" + type, handler); } else { ele[i]['on' + type] = handler; } } } }, removeHandler: function(element, type, handler) { if (ele.length === undefined) { if (ele.removeEventListener) ele.removeEventListener(type, handler, false); else if (ele.detachEvent) ele.detachEvent("on" + type, handler); else ele['on' + type] = null; } else if (ele.length === 0) { return (console.log("the element is null")); } else { for (var i = 0; i < ele.length; i ++) { if (ele[i].removeEventListener) ele[i].removeEventListener(type, handler, false); else if (ele[i].detachEvent) ele[i].detachEvent("on" + type, handler); else ele[i]['on' + type] = null; } } }, //运动方向 direction : { left : 37, up : 38, right : 39, down : 40 }, //游戏设定 setting : { size : 20, speed : 500, len : 3, func : null, direct : null } } /*Game构造器*/ function Game (food) { this.snake = new Snake(food); this.food = food; var that = this; /*Snake构造器*/ function Snake (food) { this.headX = 0; this.headY = 0; this.lastX = 0; this.lastY = 0; this.pos = []; this.f = 0; this.h = 0; this.food = food; }; Snake.prototype.init = function () { this.headX = this.headY = this.lastX = this.lastY = 0; this.pos = []; } /*创建蛇*/ Snake.prototype.create = function () { var x = g.create(g.setting.len, g.setting.size / 2), y = g.create(g.setting.len, g.setting.size / 2); //获得蛇的坐标 for (var i = 0; i < g.setting.len; i ++) { y --; this.pos.push([x, y]); if (i === 0) { g.attr(x, y, "class", "snake head"); g.attr(x, y, "touchable", "0"); } else if (i === g.setting.len - 1){ g.attr(x, y, "class", "snake tail") g.attr(x, y, "touchable", "1"); } else { g.attr(x, y, "class", "snake"); g.attr(x, y, "touchable", "0"); } } this.headX = this.pos[0][0]; this.headY = this.pos[0][1]; this.lastX = this.pos[this.pos.length - 1][0]; this.lastY = this.pos[this.pos.length - 1][1]; }; /*移动*/ Snake.prototype.move = function () { this.headX = this.pos[0][0]; this.headY = this.pos[0][1]; this.lastX = this.pos[this.pos.length - 1][0]; this.lastY = this.pos[this.pos.length - 1][1]; g.attr(this.lastX, this.lastY, "class", " "); for (var i = this.pos.length - 1; i > 0; i --) { this.pos[i][0] = this.pos[i - 1][0]; this.pos[i][1] = this.pos[i - 1][1]; } if (command.length == 0) command.push(g.setting.direct); g.setting.direct = command.shift(); command = []; switch (g.setting.direct) { case g.direction.up : this.headY -= 1; break; case g.direction.down : this.headY += 1; break; case g.direction.left : this.headX -= 1; break; case g.direction.right : this.headX += 1; break; } this.pos[0][0] = this.headX; this.pos[0][1] = this.headY; this.lastX = this.pos[this.pos.length - 1][0]; this.lastY = this.pos[this.pos.length - 1][1]; for (var i = 0; i < this.pos.length; i ++) { g.attr(this.pos[i][0], this.pos[i][1], "class", "snake"); g.attr(this.pos[i][0], this.pos[i][1], "touchable", "0"); } g.attr(this.headX, this.headY, "class", "snake head"); g.attr(this.lastX, this.lastY, "class", "snake tail"); g.attr(this.lastX, this.lastY, "touchable", "1"); var inside = g.attr(this.headX, this.headY, "inside"); if (inside == "food") { this.lastX = this.pos[this.pos.length - 1][0]; this.lastY = this.pos[this.pos.length - 1][1]; if (this.lastX == this.pos[this.pos.length - 2][0]) { if (this.lastY - this.pos[this.pos.length - 2][1] == 1) this.pos.push([this.lastX, this.lastY + 1]); else if (this.pos[this.pos.length - 2][1] - this.lastY == 1) this.pos.push([this.lastX, this.lastY - 1]); } else if (this.lastY == this.pos[this.pos.length - 2][1]) { if (this.lastX - this.pos[this.pos.length - 2][0] == 1) this.pos.push([this.lastX + 1, this.lastY]) else if (this.pos[this.pos.length - 2][0] - this.lastX == 1) this.pos.push([this.lastX - 1, this.lastY]); } g.attr(this.lastX, this.lastY, "class", "snake"); g.attr(this.lastX, this.lastY, "touchable", "0"); this.lastX = this.pos[this.pos.length - 1][0]; this.lastY = this.pos[this.pos.length - 1][1]; g.attr(this.lastX, this.lastY, "class", "snake tail"); g.attr(this.lastX, this.lastY, "touchable", "1"); score ++; this.food.create(); document.getElementById("score").innerHTML = score; g.attr(this.headX, this.headY, "inside", " "); }; //撞到自己或者墙，游戏结束 for (var i = 1; i < this.pos.length; i ++) { if (this.headX == this.pos[i][0] && this.headY == this.pos[i][1]) { that.over(); } else { continue; } } if (this.headX > (g.setting.size - 1) || this.headX < 0 || this.headY > (g.setting.size - 1) || this.headY < 0) { that.over(); } }; Snake.prototype.AIMode = function() { var head = [this.headX, this.headY], tail = [this.lastX, this.lastY], foodPos = this.food.pos, headPath = this.existPath(head, foodPos); if (headPath.length) { var test = this.fakemove(this.pos, headPath); if (test.length) { this.path(head, foodPos); } else { var fathest = this.farthest(head, foodPos, tail); if (fathest.length) { if (fathest[0] - head[0] > 0) { g.setting.direct = g.direction.right; } else if (fathest[0] - head[0] < 0) { g.setting.direct = g.direction.left; } else if (fathest[1] - head[1] > 0) { g.setting.direct = g.direction.down; } else if (fathest[1] - head[1] < 0) { g.setting.direct = g.direction.up; } } else { if (this.existPath(head, tail)) { this.path(head, tail); } else { this.path(head, foodPos); } } } } else { var fathest = this.farthest(head, foodPos, tail); if (fathest.length) { if (fathest[0] - head[0] > 0) { g.setting.direct = g.direction.right; } else if (fathest[0] - head[0] < 0) { g.setting.direct = g.direction.left; } else if (fathest[1] - head[1] > 0) { g.setting.direct = g.direction.down; } else if (fathest[1] - head[1] < 0) { g.setting.direct = g.direction.up; }; } else { if (this.existPath(head, tail).length) { this.path(head, tail); } else { this.struggle(head); } } } }; /* 算法JS实现 */ Snake.prototype.path = function(sta, end) { var startX = sta[0], startY = sta[1], distance = this.existPath(sta, end); if (distance.length > 1) { if (distance[1][0] - startX > 0) { g.setting.direct = g.direction.right; } else if (distance[1][0] - startX < 0) { g.setting.direct = g.direction.left; } else if (distance[1][1] - startY > 0) { g.setting.direct = g.direction.down; } else if (distance[1][1] - startY < 0) { g.setting.direct = g.direction.up; } } } /* 贪吃蛇头部附近找个距离食物最远的有效点 */ Snake.prototype.farthest = function(start, end, tail) { var startX = start[0], startY = start[1], endX = end[0], endY = end[1], que = [], distance = []; for (var i = -1; i <= 1; i ++) { if (i === 0) { continue; } else { if (startX + i < g.setting.size && startX + i >= 0 && g.attr(startX + i, startY, "touchable") === '1' && this.existPath([startX + i, startY], tail).length) { que.push([startX + i, startY]) } if (startY + i < g.setting.size && startY + i >= 0 && g.attr(startX, startY + i, "touchable") === '1' && this.existPath([startX, startY + i], tail).length) { que.push([startX, startY + i]) } } } for (var i = 0; i < que.length; i ++) { var dis = Math.sqrt(Math.pow(endX - que[i][0], 2) + Math.pow(endY - que[i][1], 2)); distance.push([dis, que[i]]); } distance.sort(function(a, b) { return b[0] - a[0]; }) if (distance.length) { return distance[0][1]; } else { return distance; } } /* 移动一条假蛇去吃食物以检查路径是否安全 */ Snake.prototype.fakemove = function(pos, path) { var temp = []; if (path.length >= pos.length) { for (var i = path.length - 1; i >= path.length - pos.length; i --) { if (i === path.length - pos.length) { g.attr(path[i][0], path[i][1], "touchable", '1'); } else { g.attr(path[i][0], path[i][1], "touchable", '0'); } } for (var i = 0; i < pos.length; i ++) { g.attr(pos[i][0], pos[i][1], "touchable", "1"); } temp = this.existPath(path[path.length - 1], path[path.length - pos.length]); } else { if (path.length > 2) { for (var i = pos.length - 1; i >= pos.length - path.length; i --) { g.attr(pos[i][0], pos[i][1], "touchable", "1"); } for (var i = 0; i < path.length; i ++) { g.attr(path[i][0], path[i][1], "touchable", "0"); } temp = this.existPath(path[path.length - 1], pos[pos.length - path.length]); } else { g.attr(pos[pos.length - 1][0], pos[pos.length - 1][1], "touchable", "1"); for (var i = 0; i < path.length; i ++) { g.attr(path[i][0], path[i][1], "touchable", "0"); } temp = this.existPath(path[path.length - 1], pos[pos.length - 1]); } } for (var i = path.length - 1; i >= 0; i --) { g.attr(path[i][0], path[i][1], "touchable", "1"); } for (var i = pos.length - 2; i >= 0; i --) { g.attr(pos[i][0], pos[i][1], "touchable", "0"); } g.attr(pos[pos.length - 1][0], pos[pos.length - 1][1], "touchable", "1"); return temp; } /* BFS算法实现寻找路径 */ Snake.prototype.existPath = function(start, end) { var visited = [], que = [], parent = []; var sta = start; for (var i = 0; i < g.setting.size; i ++) { visited[i] = []; parent[i] = []; for (var j = 0; j < g.setting.size; j ++) { visited[i][j] = false; parent[i][j] = [-1, -1]; } } var tempque = []; tempque.push(start); if (start) { if (visited[start[0]]) visited[start[0]][start[1]] = true; } while (tempque.length) { start = tempque.shift(); var x = start[0], y = start[1]; for (var i = -1; i <= 1; i ++) { if (i === 0) { continue; } else { if (x + i < g.setting.size && x + i >= 0 && (g.attr(x + i, y, "touchable") === '1') && !visited[x + i][y]) { tempque.push([x + i, y]); visited[x + i][y] = true; parent[x + i][y] = [x, y]; if (x + i === end[0] && y === end[1]) { var temp = end; while (temp && temp[0] != -1) { que.unshift(temp); temp = parent[temp[0]][temp[1]]; } } } if (y + i < g.setting.size && y + i >= 0 && (g.attr(x, y + i, "touchable") === '1') && !visited[x][y + i]) { tempque.push([x, y + i]); visited[x][y + i] = true; parent[x][y + i] = [x, y]; if (x === end[0] && y + i === end[1]) { var temp = end; while (temp && temp[0] != -1) { que.unshift(temp); temp = parent[temp[0]][temp[1]]; } } } } } } return que; } /* 实在没辙就只能就近做S形运动苟延残喘 */ Snake.prototype.struggle = function(head) { var t = [-1, 1], x = head[0], y = head[1], que = [], die = 0; switch(g.setting.direct) { case g.direction.up: if (y - 1 < 0 || g.attr(x, y - 1, "class").indexOf("snake") != -1) { die = 1; } break; case g.direction.down: if (y + 1 >= g.setting.size || g.attr(x, y + 1, "class").indexOf("snake") != -1) { die = 1; } break; case g.direction.left: if (x - 1 < 0 || g.attr(x - 1, y, "class").indexOf("snake") != -1) { die = 1; } break; case g.direction.right: if (x + 1 >= g.setting.size || g.attr(x + 1, y, "class").indexOf("snake") != -1) { die = 1; } break; } if (die) { for (var i = 0; i < 2; i ++) { if (x + t[i] < g.setting.size && x + t[i] >= 0 && g.attr(x + t[i], y, "class") && g.attr(x + t[i], y, "class").indexOf("snake") == -1) { que.push([x + t[i], y]); } if (y + t[i] < g.setting.size && y + t[i] >= 0 && g.attr(x, y + t[i], "class") && g.attr(x, y + t[i], "class").indexOf("snake") == -1) { que.push([x, y + t[i]]); } } if (que.length) { if (que[0][0] - head[0] > 0) { g.setting.direct = g.direction.right; } else if (que[0][0] - head[0] < 0) { g.setting.direct = g.direction.left; } else if (que[0][1] - head[1] > 0) { g.setting.direct = g.direction.down; } else if (que[0][1] - head[1] < 0) { g.setting.direct = g.direction.up; } } } } }; /*创建格子*/ Game.prototype.pannel = function () { var t = []; t.push(""); for (var i = 0; i < g.setting.size; i ++) { t.push("">"); for (var j = 0; j < g.setting.size; j ++) { t.push(""); } t.push(""); } t.push(""); document.getElementById("pannel").innerHTML = t.join(""); }; /*初始化游戏*/ Game.prototype.init = function () { score = 0; document.getElementById("score").innerHTML = score; this.snake.init(); speed.disabled = start.disabled = false; if (g.setting.func) { window.clearInterval(g.setting.func); } for (var x = 0; x < g.setting.size; x ++) { for (var y = 0; y < g.setting.size; y ++) { g.attr(x, y, "class", " "); g.attr(x, y, "inside", " "); } } } /*游戏开始*/ Game.prototype.start = function () { this.food.create(); this.snake.create(); g.setting.direct = g.direction.down; var that = this; g.setting.func = window.setInterval(function() { that.snake.AIMode(); that.snake.move(); }, g.setting.speed) //蛇移动 //g.setting.func = window.setInterval(function() { // snake.move(); //}, g.setting.speed); } /*监听键盘*/ Game.prototype.listen = function (e) { e = e || event; command.push(Math.abs(e.keyCode - g.setting.direct) != 2 && e.keyCode > 36 && e.keyCode < 41 ? e.keyCode : g.setting.direct); } /*游戏结束*/ Game.prototype.over = function () { alert("game over XD!"); this.init(); }; /*Food构造器*/ function Food () { this.pos = []; }; /*创建食物*/ Food.prototype.create = function () { var that = this; var x = g.create(0, g.setting.size), y = g.create(0, g.setting.size); //检查是否与蛇的位置重合 var c = g.attr(x, y, "class"); if (c.indexOf("snake") != -1) return this.create(); else { g.attr(x, y, "class", "food"); g.attr(x, y, "inside", "food"); } this.pos = [x, y]; }; var command = [], gameAi, foodAi, speed = document.getElementById("gameSpeed"), start = document.getElementById("start"), score = 0; foodAi = new Food(); gameAi = new Game(foodAi); gameAi.pannel(); gameAi.init(); function gameStart() { this.disabled = true; g.setting.speed = speed.options[speed.selectedIndex].value; speed.disabled = true; gameAi.start(); //window.onkeydown = game.listen; }; function switchChange() { var cla = this.firstChild.className.split(" "); for (var i = 0; i < cla.length; i ++) { if (cla[i] == "switch-animate") { cla.splice(i, 1); break; } } cla = cla.join(" "); this.firstChild.className = cla; } function switchAnimate() { var cla = this.firstChild.className.split(" "); for (var i = 0; i < cla.length; i ++) { if (cla[i] == "switch-off") { cla.splice(i, 1, "switch-on"); break; } else if (cla[i] == "switch-on") { cla[i] = "switch-off"; break; } } cla.push("switch-animate"); cla = cla.join(" "); this.firstChild.className = cla; } g.addHandler(start, "click", gameStart); g.addHandler(document.getElementsByClassName("switch"), 'mousedown', switchChange); g.addHandler(document.getElementsByClassName("switch"), 'mouseup', switchAnimate); })()